The cooling fan has been widely used to remove heat generated by a variety of electronic devices and components, such as central processing units (CPU), servers, power supplies, communication chassis, and telecommunication base stations. The cooling fan is also often used in very severe environments, such as humid, wet, and salt spray environments. Since a general cooling fan is not provided with any protective structure against water and salt spray, the stator inside the fan is subject to corrosion caused by invading water and salt spray. In some worse conditions, the circuit board of the fan is corroded and damaged to thereby shorten the service life of the fan.
Two solutions have been proposed to overcome the above problems. One of the two solutions is insert molding technique, and the other solution is pour molding technique. In insert molding, first arrange the stator and the circuit board of the fan on a fan frame to form a subassembly and then position the subassembly in a mold before injecting a large quantity of molten plastic material into the mold. When the molten plastic material is cooled and set in the mold, the above said subassembly in the molded plastic material is removed from the mold, that is, the mold is removed.
Therefore, the stator and the circuit board enclosed in the molded plastic material are protected against external water. According to the pour molding technique, the stator and the circuit board are first assembled to the fan frame to form a subassembly, and then, put the subassembly in a mold and pour a large quantity of adhesive material into the mold. After the adhesive material is hardened in the mold, the subassembly enclosed in the molded adhesive material is removed from the mold, that is, the mold is removed. Therefore, the stator and the circuit board enclosed in the adhesive material are protected against external water.
While the conventional insert molding solution and pour molding solution can enclose the stator and the circuit board in the molded plastic material and the molded adhesive material, respectively, to achieve the purpose of protecting the stator and the circuit board against external water, they all require a mold for positioning the stator and the circuit board therein for subsequent insert molding or pour molding process. Further, additional time and labor are needed to remove the mold when the insert molding or pour molding process is completed. Therefore, the conventional insert molding solution and pour molding solution involve complicated manufacturing process to consume more time and labor and result in lowered productivity and increased manufacturing cost. In brief, the conventional solutions for protecting the stator and circuit board against external moisture or salt spray have the following disadvantages: (1) increased material cost; (2) complicated manufacturing process; and (3) consuming more time and labor.
It is therefore tried by the inventor to develop an improved waterproof motor stator structure to overcome the disadvantages in the conventional solutions.